1. Field of the Invention
The present invention relates to a content distribution based on digital broadcasting such as ground-wave digital broadcast, satellite digital broadcast or the like.
2. Description of the Related Art
Broadcasting or distribution of music contents by using a broadcast network based on a digital broadcasting satellite or the like, or a communication network based on a cellular phone or the like have been recently proposed or put into practice by various enterprises, etc.
In general, the digital broadcast supports one-to-multiple communications, and it can transmit data having a large data size to many users at the same time. Therefore, particularly when a large amount of data such as a music content or the like is distributed, a broadcast infrastructure is more effectively used, from the viewpoint of the communication cost and the communication speed, than when a communication infrastructure such as a cellular phone or the like is used.
The broadcast infrastructure has no re-transmitting function. Therefore, once a user temporarily fails to obtain some data (hereinafter referred to as “missing part”) due to instantaneous interruption while the user receives the data on the move (hereinafter referred to as “reception on the move”), the user cannot resume the data thus lost. Further, since the broadcast is carried out according to a predetermined program schedule, the content has been usually edited in advance and thus in many cases it is different from the original. Therefore, in many cases, some pieces of data are missing from the content obtained through a broadcast network or some differences exist between the content thus obtained and the original. Therefore, it is difficult to obtain the data having the perfect content.
On the other hand, a data re-transmission request is easy in a communication infrastructure such as a cellular phone, PHS (Personal Handy Phone System) or the like. However, the communication cost is very high and the communication speed is low because it supports one-to-one communications. Therefore, this communication infrastructure is unsuitable for the distribution of data having a large data size such as a music content, from the viewpoint of the communication cost and the communication time.